Speaker
Description
The High Intensity and Energy ISOLDE (HIE-ISOLDE) upgrade project at CERN includes the deployment of new superconducting accelerating structures operated at 4.5 K (ultimately of six cryo-modules) installed in series, and the refurbishing of the helium cryo-plant previously used to cool the ALEPH magnet during the operation of the LEP accelerator from 1989 to 2000. The helium refrigerator is connected to a new cryogenic distribution line, supplying a 2000-liter storage dewar and six interconnecting valve boxes, one for each cryo-module. After a first operation period with one cryo-module during six months in 2015, a second cryo-module has been installed and operated during 2016. The operation of the cryo-plant with these two cryo-modules has required significant consolidations and tunings for the compressor, the cold box and the cryogenic distribution system in order to reach nominal and stable operational conditions. The present paper describes the commissioning results and the lessons learnt during the operation campaign of 2016 together with the preliminary experience acquired during the 2017 operation phase with a third cryo-module.